100% of 3 Pros
No, you do not, but you need to understand the environment where you are working.
I suggest a basic knowledge of it. Cord wil have 3 color coded wires within the outer plastic. Positive, Negative, and Ground. Wire strippers are used to exposed the copper in these 3 wires. Afterward they are twisted together clockwise and capped with a plastic cone also turned clockwise. Really just dont touch wires. Even if you're told its dead, look for yourself on the fuse box/test it.